The present invention relates to a new and distinct and superior variety of the pawpaw which is of interest for its fruit.
The speciesxe2x80x94Asimina triloba (L.) Dunalxe2x80x94is the largest native edible fruit of North America, a member of the Annonaceae family, and thus a relative of the cherimoya, sweetsop, guanabana and custard apple (Annona cherimola, A. squamosa, A. muricata and A. reticulata), all of which are popular fruits that are widely cultivated in tropical and subtropical regions of the world, including southern Florida and southern California. The pawpaw is the only truly temperate member of the Annonaceae, being indigenous to a region stretching from the Great Lakes to the Gulf Coastal Plain and from the Chesapeake Bay to the Great Plains.
Currently, the pawpaw is considered to be semi-domesticated. Native Americans casually cultivated the tree, as did the white settlers who displaced them. The selection, propagation and naming of pawpaw varieties from the wild has been practiced for more than a century, and the backyard cultivation of pawpaws for personal use is not uncommon in Appalachia and parts of the Midwest. Numerous unregistered, unpatented varieties are available in the mail-order nursery trade.
Commercial cultivation of pawpaw has not developed, however. The fruit is fragile and highly perishable which makes transport difficult. And scientific attention towards improving the fruit, its culture and its postharvest handling has received little attention until recently. The lack of high quality cultivars that meet the requirements of producers and consumers is the foremost reason that commercial cultivation has not been undertaken.
The present invention, named xe2x80x98Aidfievatexe2x80x99 by the developer, is the second of three new and distinct varieties of pawpaw, each of which represents a great improvement over existing pawpaw varieties because of higher yields, superior flavor, fewer seeds and firmer flesh. The other two varieties are xe2x80x98Wansevwanxe2x80x99, which is the subject of co-pending application Ser. No. 09/954,536, and xe2x80x98Levfivxe2x80x99, which is the subject of co-pending application Ser. No. 09/954,186. These varieties possess the minimum overall qualities required for the development of a commercial pawpaw industry. The primary use of this pawpaw variety will be for fresh eating as a dessert fruit. Secondary use will be in processed products such as ice cream, yogurt, juice and cosmetics. Of the three, the variety xe2x80x98Aidfievatexe2x80x99 is outstanding for ease of harvest, and for consistency of size and shape.
The variety xe2x80x98Aidfievatexe2x80x99 was developed by R. Neal Peterson as the result of a breeding project to improve the pawpaw, which he began in 1980. The project was conducted during a period when Peterson was employed as an economist with the Economic Research Service of the United States Department of Agriculture in Washington, D.C. However, because Peterson was not employed in any capacity as a horticulturist or other researcher in the biological sciences, and no Department of Agriculture plant stock, facilities or information was used, the United States government has no interest in the rights to the claimed variety.
The germplasm for Peterson""s breeding project came principally from the surviving remnants of five historic collections of pawpaw dating to the early twentieth century that were the work of the most prominent pawpaw collectors and breeders of the time, and whose named material was no longer propagated or otherwise available. In 1982 germ plasm (open-pollinated seed) was collected from these remnants and included with open-pollinated seed from named cultivars, which became the germ plasm for his own breeding and selection work.
In 1983 the seed was germinated and in the following spring 808 accessions were planted at the University of Maryland experiment station, the Wye Research and Education Center, Queenstown, Md. Since then, the orchard has been supervised by the inventor, with basic staff support from the university. Basic tasks such as fertilizing, spraying and mowing were conducted by the station staff. The inventor pruned, weeded, and collected data on growth rates, flowering, fruit set, yields, cluster size, fruit size and fruit quality, including data from taste panels which he organized.
In 1991, the inventor analyzed four years of data, and concluded in identifying eleven trees as superior for further study. Nine of these are involved in regional variety trials around the country and have been termed advanced numbered selections. After nine additional years of observation, the original nine were narrowed to three that were consistently of the highest quality. One of these bears the accession number PPF 8-58 and is the variety that is the subject of this application. The original tree PPF 8-58 is 18 years old. This new variety, named xe2x80x98Aidfievate,xe2x80x99 originated as an open-pollinated seedling from a pawpaw tree on the grounds of the Blandy Experimental Farm, Boyce, Va., which tree was given the label BEF-30 by the inventor. Pawpaw BEF-30 is believed to have been a cataloged accession of the Blandy Experimental Farm""s collection of Asimina triloba (circa 1922-1955) although records to support this contention are now missing. To our knowledge BEF-30 has never been asexually propagated.
In 1994, Peterson began topworking the Wye orchard to his eleven advanced numbered selections, plus named varieties. Topworking was accomplished using bark-inlay grafting and chip-budding. Grafting of xe2x80x98Aidfievatexe2x80x99 was easy by either method, and gave a medium-high percentage of success. Replicates of xe2x80x98Aidfievatexe2x80x99 now number more than 15 at the Wye, having been propagated through successive cycles of grafting over seven years. The rootstock for these grafts were mature seedling pawpaw trees growing in the orchard, and were a portion of the original accessions from 1983, described previously. Six grafted trees of xe2x80x98Aidfievatexe2x80x99 have now been in bearing since 1997 and demonstrate that asexual reproduction of this new and distinct variety preserves the desirable characteristics of the variety and establishes and stably transmits those characteristics through successive propagation at the Queenstown location.
xe2x80x98Aidfievatexe2x80x99 is outstanding in its ease of harvesting and excels in vigor, yields, flavor, and small cluster size. The fruit is medium in size, on average 200 gm for well-pollinated fruit, and may exceed 280 gm. It is usually borne in clusters of one, two or three fruits. Fruit size and shape is relatively uniform and consistent as compared to most pawpaws. Fruit shape is typically ovate to nearly round. Skin thickness is medium-thin, slightly thicker than is typical for the species. Skin color is pale green and glaucous, and at the stage for picking exhibits a noticeable color-break as the skin becomes paler and more yellowish. This color break is reliable and can be easily discerned with practice. The composition of the fruit is moderately fleshy, as measured by the seed-to-fruit ratio. The size of seeds is medium. The aroma of the fruit before and after cutting is pleasant and quite mild. The flavor is very good, though not as good as xe2x80x98Wansevwanxe2x80x99xe2x80x94mild, sweet, free of bitterness or astringency, with a pleasant aftertaste. The pungent asiminous component that is uniquely pawpaw and that many people find objectionable is weak to absent. The flesh is firmer than average and very smooth with no detectable fiber or grit, although a certain rubberiness in texture sometimes detracts from an otherwise pleasant mouth-feel. Fruit cracking is a problem on vigorous rootstocks. The ripening period at Queenstown has been mid-season, September 6 to 14, more or less, depending on the degree of heat in the preceding months.
Several non-fruit characters also serve to distinguish xe2x80x98Aidfievatexe2x80x99 from other pawpaws. The aspect of the leaf in full sun is horizontal, a character that is unique to this variety and that contrasts with the typical drooping aspect of pawpaw leaves. This horizontal leaf aspect allows for easy inspection of the tree""s interior where the fruit develops, and this simplifies picking. The branching habit is more vertical than is typical of the species. Flower measurements when taken as a whole may also identify xe2x80x98Aidfievate.xe2x80x99 Its flower is borne on a longer peduncle than average, is larger than average, and is more loosely closed in the female stage than is typical for pawpaw. For exact data, see the detailed description and accompanying photographs.
This variety is susceptible to Talponia plummeriana, the pawpaw peduncle moth, is susceptible to Eurytides marcellus, the zebra swallowtail butterfly, and is believed to be susceptible to pawpaw decline disease, the same in all cases as the species. This variety responds very vigorously to pruning and is difficult to control in size with pruning alone. It should be grafted onto less vigorous rootstocks both to control ultimate tree size and to correct the tendency towards fruit cracking.